CW Flashcards
What is the neutralisation reaction word equation?
Acid + base > salt + water
How do you recover the salt in neutralisation?
Using the evaporation technique. The solution is poured in an evaporating basin, which is heated by a bunsen burner and left to evaporate until salt crystals have been formed.
What is an indicator?
Indicators can tell whether a substance is an acid or base by changing colour.
What are some examples of indicators?
Some common indicators are: universal indicator, litmus, methyl orange.
What does PH stand for?
Potential of Hydrogen.
All matter is…
composed of atoms and has mass.
What is the rule concerning matter?
Matter can neither be created or destroyed in a reaction. The total number of atoms in the reactants = the total number of atoms in the products.
What are compounds?
Compounds are new substances that are formed in chemical reactions when atoms rearrange. A compound is two or more elements joined together chemically.
Identify the chemical formula for the compound: Water
H2O
Identify the chemical formula for the compound: Sodium Chloride
NaCl
When does a neutralisation reaction occur?
Neutralisation reactions occur when an acid and a base chemically react with one another to produce a salt and water.
What are some examples of neutralisation reactions in the home.
- Neutralisation of Acids caused by bacteria in your mouth and toothpaste
- Neutralisation of acids in your stomach and antacid tablets
An acid and a metal chemically react to produce what?
A salt and a hydrogen gas.
What is the general word equation that is used to describe an acid-metal reaction?
Acid + Metal ———> salt + hydrogen
An example acid-metal reaction is the pop-test which is achieved by reacting magnesium ribbon (metal) and hydrochloric acid which produces hydrogen (H2): Mg + HCl———> MgCl + H2
(REACTANTS) (PRODUCTS)
Identify the chemical formula for the compound: Citris Acid
C6H8O7
Identify the chemical formula for the compound: Sulfuric Acid
H2SO4
Identify the chemical formula for the compound: Carbon Hydroxide
CH4
What happens during a chemical reaction?
A chemical reaction is said to have occurred when a new product is formed. Atoms from the original chemicals, also known as reactants are rearranged to form new products in a chemical reaction.
What is a chemical equation?
A chemical equation is a way of communicating specific information about a reaction. Chemical equations can be written in words or they can be written using molecular formulae Eg. Word equation
Hydrogen + Oxygen —> water
H2 + O —-> H2O
What does the arrow in a chemical equation mean?
The arrow must be used in chemical equations. It means “produces”
What do indicators do?
Indicators can tell whether a substance is an acid or base by changing colour.
Some common indicators are…
Universal Indicator, Litmus, methyl orange.
What are reactants and products?
Reactants - starting materials/chemicals in a reaction
Products - new chemicals formed by a reaction
What is an exothermic reaction?
An exothermic reaction is a chemical reaction that releases energy by light or heat.
What is an endothermic reaction?
An endothermic reaction is a chemical reaction in which the system absorbs energy from its surroundings
eg. Photosynthesis, Melting Ice, Baking Bread, Cooking an Egg
Chemical reactions involve energy transfer and can either be…
exothermic or endothermic.
What is corrosion?
The decay (loss of metallic properties in strength, lustre or shine, and electrical conductivity) of a metal that occurs when a metallic substance oxidises after exposure to gases or liquids.
What is a chemical equation of corrosion?
Fe + O2 > FeO2
Metal + oxygen > metal oxide
Ways to prevent corrosion
- Turn to non-corrosive metals such as Aluminium and stainless steel.
- Keep the area around the metal surface dry.
- Use drying agents and moisture barrier products.
- Use corrosive inhibitors (lacquers, painting, grease oil
- Galvanising (cover the metal with zinc to slow down the corrosive process)
THE RATE OF A CHEMICAL REACTION CAN BE CHANGED BY ALTERING THE TEMPERATURE. If the temperature is increased…
- The reactant particles move more quickly - They have more energy - The particles collide more often because of this, and more of the collisions are successful - Thus the rate of reaction increases.
THE RATE OF A CHEMICAL REACTION CAN BE CHANGED BY ALTERING THE TEMPERATURE. If the temperature is decreased…
- Molecules are slower - Collide less sometimes you will mix solutions in ice so that the temperature of the system stays cold and the rate of reaction is slower
